A Bangladeshi labor activist is urging Wal-Mart and other well-known American clothing brands to call on the government to drop the criminal "incitement" charges leveled against her after she rallied to improve working conditions at garment factories there.

"The brands can really play a vital role when we are put in jail," activist Kalpona Akter told ABC News. "They are the most powerful, and can put pressure onto the factory owners and the Bangladeshi government to tell them these charges should be dropped."

As ABC News reported this week, nearly 500 workers have died in fires at the high-rise Bangladesh clothing factories where American brands have been enjoying the world's cheapest labor costs. The factories lacked basic fire safety staples, such as sprinklers and fire escapes, and some workers said it was common for companies to padlock the exits to help prevent theft during the workday.

Tommy Hilfiger -- whose famous label was traced to several of the factories -- acknowledged in an interview that the conditions are "unacceptable" and "tragic." Hilfiger pledged to go to Bangladesh to demand better conditions, and the company that owns his brand, PVH Corp., responded to the ABC News investigation by committing between $1 million and $2 million to make significant improvements.

But for Akter, who has been fighting inside Bangladesh for better working conditions, efforts to persuade factory owners to improve safety standards have brought threats of imprisonment from a government where garment company owners wield great influence.

In 2010, after she led a drive to mobilize workers to demand more protection from the deadly fires, Akter and two of her coworkers were imprisoned for more than a month. During the imprisonment, she says she and her colleagues were beaten.

Bangladesh embassy officials told ABC News she was involved "in fomenting unrest and agitation in the garments sector … contrary to the interest of the common workers as well as the country."

Akter was released after heavy international pressure from labor groups, but the government has continued to pursue seven criminal charges against her -- charges that could bring a lengthy jail term.

In an interview with ABC News, Akter said she has been willing to fight for better working conditions because she experienced the indignity of the factories herself -- she began sewing clothes for American labels when she was 12 years old.

"I was the worker," she said. "I worked 23 days in a row, sleeping on the shop floor, taking showers in the [factory restroom], drinking unsafe water, being slapped by the supervisor. I don't want to see [that] anymore."

In 2000, she joined with other former garment workers to launch the Bangladesh Center for Worker Solidarity, a non-profit organization that focused on empowerment of working women, the rights of children, and the security of working families and communities. Based in the capital city of Dhaka, with five offices and 31 staff, the group conducted worker rights training and engaged in legal and public advocacy on behalf of garment workers.